Question

You have taken over an abandoned project of drilling a water well. You find the hole is 22 feet deep. After 3 hours of drilling, the depth is 33.4 ft. What depth would you expect to reach after 15 hours?

Answer 1

33.4-22= 11.4
11.4/3= 3.8
3.8 is one hour. 
3.8*15
57 ft. for the 15 hours.
57+33.4= 90.4 ft.
The answer is 90.4 ft.